Selective catalytic reduction (“SCR”) exhaust aftertreatment systems are an important technology for reducing NOx, emissions from internal combustion engines. SCR systems generally include a source of storage for the diesel exhaust fluid (DEF), a doser that includes at least one of a pump unit for pressurizing the DEF and a metering unit for providing a controlled amount or rate of DEF, and an injector which provides a DEF solution to a decomposition region of an exhaust flow path located upstream from an SCR catalyst. Many SCR systems also utilize pressurized gas to assist the flow of DEF to the injector. While providing reductions in NO, emissions, SCR systems suffer from a number of shortcomings and problems.
The DEF injected into the exhaust flow may not properly mix with the exhaust flow. In some instances, the DEF can puddle along an inner wall of the exhaust system, forming a deposit over time. Thus, there is a need for advancements mitigating these and other shortcomings associated with injection systems for delivery of DEF through a nozzle connected to an exhaust system.